Necrotizing Fasciitis in Cats

Necrotizing fasciitis in cats, commonly referred to as the flesh eating bacteria, is a rapidly spreading bacterial infection of the facial and subcutaneous tissues. Necrotizing fasciitis in cats is most commonly caused by the bacteria known as Streptococcus canis, but other reported cases have been caused by other strains of bacteria including Prevotella bivia and Acinetobacter baumannii. One of these three strains of bacteria can enter the cat’s skin through a point of injury, such as trauma to the skin caused by a bite or deep scratch. Signs of an infection usually begin to appear just a few days after being infected and include localized pain, edema and localized erythema. The death rate of necrotizing fasciitis in cats is rather high and not all felines that recover make a full recovery. As tissue reconstruction is often necessary, a feline may lose the functionality of her tissues, which is why professional veterinary consultation is a must. 

Clinical signs of necrotizing fasciitis in cats will appear within a few days of infection. In beginning stages of infection, the skin will develop small skin lesions that soon turn into large regions of ulceration and necrosis. The affected skin separates itself, uncovering hidden flesh underneath the skin and local to total body pain is to be expected. Necrotizing fasciitis in cats spreads quickly and in a short amount of time will cause the feline to develop symptoms including the following: 

• Disseminated intravascular coagulation (formation of blood clots)
• Melena (dark, tarry feces)
• Hemoptysis (coughing up blood)
• Ecchymosis (bruising or discoloration of skin from bleeding)
• Multiple organ failure 
• Hypoalbuminemia (low blood albumin)
• Skeletal muscle damage 
• Leukocytosis (high white cell count)
• Peripheral underperfusion 
• Tachycardia (rapid heart rate)
• Depression 
• Fever 
• Shock 

Necrotizing fasciitis in cats is caused by a localized streptococcal infection with a systemic toxemia effect. The majority of necrotizing fasciitis cases are caused by the Streptococcus canis bacterial strain, but Prevotella bivia and Acinetobacter baumannii organisms have been reported to affect felines as well. Minor skin injuries are the common point of entry for these organisms, such as a bite wound, cut or scratch on the cat’s skin. Necrotizing fasciitis is commonly seen in outdoor felines, shelter cats, and in hoarding facilities. Necrotizing fasciitis is more commonly seen in dogs and is also known for its zoonotic potential for infecting humans. 

Your veterinarian will base his or her diagnosis on the clinical signs your cat is displaying, histopathological results, and surgical findings. However, the vet cannot make an absolute positive diagnosis of necrotizing fasciitis until a positive culture of the aetiological agent (bacterial strain causing the infection) has been made. Therefore, your veterinarian will start diagnostic tests with a physical exam, followed by a review of your cat’s medical history. You will be asked about your cat’s condition, how long the feline has had clinical signs of an infection and if she/he suffered any recent trauma to speak of. An analysis of your cat’s blood, urine and feces will likely be performed to rule out possible causes of the cat’s condition. Following routine diagnostic procedure, the veterinarian will likely swab the skin to perform a skin culture and/or take a sample of skin upon biopsy for histopathological examination. 

Necrotizing fasciitis is treated with aggressive surgical excision of all necrotic tissues to prevent the bacteria from spread onto unaffected, healthy skin. A delay in surgical debridement will increase the feline’s chances of mortality, therefore, treatment must be rapid. Intravenous fluids infused with a strong antibiotic will be administered to the feline to aid in fighting the bacteria. Although an antibiotic will aid in treating the necrotizing fasciitis infection, therapeutic drugs alone, without surgical excision, will prove ineffective. 

After the necrotic (dead) tissues have been surgically removed, your cat will require skin grafts under reconstructive surgery. If your cat has enough excess tissue to be removed from another area of the body, tissues can be directly transferred from that area. However, if your cat is relatively lean and does not posses enough excess tissue, a donor may be required. Ask your veterinarian about a skin donor program for your cat and what is required of the feline to receive necessary tissues. 

The prognosis for necrotizing fasciitis in cats is guarded to poor. Felines that are diagnosed early and receive aggressive treatment have a better outcome, but may not make a full recovery. The feline will appear overall healthy, but the grafted tissues are non-functional with poor nerve stimulation and poor elasticity.  Due to the rarity of this disease, a prompt diagnosis may be difficult to obtain as the likelihood of a cat being affected by necrotizing fasciitis is extremely low. For humans, the chances of being infected with a flesh eating bacteria is one to five cases in 100,000 people and, although the rate believed to be slightly higher in cats, the chances are still fairly low.